 A great deal of volcanic activity has occurred at Newberry Volcano, which was last active about 1,300 years ago.It has one of the largest collections of cinder cones, lava domes, lava flows and fissures in the world.Medicine Lake Volcano has erupted about eight times in the past 4,000 years and was last active about 1,000 years ago when rhyolite and dacite erupted at Glass Mountain and associated vents near the caldera's eastern rim.